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Speaker 1: Welcome to brain Stuff from how stuff works dot com

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Speaker 1: where smart Happens. Him Marshall Brain with today's question, how

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Speaker 1: do the new full body scanners at airports work? And

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Speaker 1: this really is an interesting question because there's two parts

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Speaker 1: to it. There's the actual technology of the scanners, but

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Speaker 1: there's also the huge uproar they're causing right now, So

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Speaker 1: we can look at both aspects of that and see

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Speaker 1: how they're converging right now. The thing you notice if

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Speaker 1: you've been watching the news is that there's a huge

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Speaker 1: uproar around these new full body scanners that are being

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Speaker 1: deployed at airports around the United States right now. There

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Speaker 1: are people loudly claiming that the t s A is

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Speaker 1: handcuffing them to chairs for refusing to be scanned, for example,

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Speaker 1: and the t s A responding that it never happened.

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Speaker 1: There are videos showing little toddlers dreaming during pat downs.

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Speaker 1: There are calls for congressional oversight, passenger boycotts, acts of

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Speaker 1: private protest t s A abolishment. Even in New Jersey

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Speaker 1: there's claiming that they're going to stop the t s A,

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Speaker 1: and in Orlando they claim that they're going to replace

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Speaker 1: the t s A with private contractors, so there really

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Speaker 1: is a big debate going on right now. There are

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Speaker 1: many reasons why people tend not to like these new

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Speaker 1: full body scanning machines, but the two primary complaints are

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Speaker 1: health concerns from X ray radiation and privacy concerns, both

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Speaker 1: from being groped during pat downs if you opt out

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Speaker 1: of the scan and from the possibility of scanned photos

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Speaker 1: being distributed. Whether you love or hate the Transportation Safety

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Speaker 1: Administration and its mission, the mission is clear. The t

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Speaker 1: s a's goal is to keep passengers from carrying weapons

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Speaker 1: and explosives onto airplanes. We can generally agree as a

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Speaker 1: society that this is a worthwhile goal. No one us

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Speaker 1: to see a terrorist wearing a suicide bomb blow up

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Speaker 1: and the airplane and kill three people in the air.

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Speaker 1: One obvious way to carry the weapons on is in

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Speaker 1: luggage and handbags. The other way is to attach them

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Speaker 1: to your body. The X ray machines that we use

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Speaker 1: to scan luggage are generally considered to be safe and effective,

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Speaker 1: so no one's really worrying about those. But when it

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Speaker 1: comes to searching the bodies of passengers, the use of

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Speaker 1: metal detectors and normal pat downs appears to have problems. First,

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Speaker 1: metal detectors can't detect some explosives, which often don't contain

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Speaker 1: much metal, and a normal pat down may not be

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Speaker 1: very effective. Passengers wiggle and complain. Passengers are naturally reluctant

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Speaker 1: to have their personal areas explored by a stranger's hands. Therefore,

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Speaker 1: the person doing the pat down may not be very thorough.

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Speaker 1: And if certain parts of the body, for example, the

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Speaker 1: genital areas or certain types of people for example toddlers,

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Speaker 1: are deemed inappropriate for padding, then those obvious places to

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Speaker 1: hide weapons. What is an alternative to full body scanners?

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Speaker 1: One alternative would be to have passengers enter a private

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Speaker 1: booth in which he or she would remove all clothing

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Speaker 1: and hand it to an agent. Then the clothing and

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Speaker 1: the passengers naked body or photographs thereof would be examined.

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Speaker 1: Then the passenger would redress and exit the screening area.

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Speaker 1: This would be effective, but it has two problems. First, many,

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Speaker 1: perhaps most, passengers would openly rebel, and second, it could

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Speaker 1: really slow down the screening process, making it more expensive.

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Speaker 1: There might also be problems with pornography and child pornography laws.

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Speaker 1: Instead of making everyone get naked in a booth. The

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Speaker 1: t s A has instead deployed two types of screening

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Speaker 1: machines that let passengers skip the undressing part. The machine

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Speaker 1: undresses you by either using X rays or millimeter radio waves.

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Speaker 1: The backscatter X ray technique is the one getting the

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Speaker 1: most publicity at the moment. In this machine, visualize a

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Speaker 1: beam of low power X rays, similar to a laser

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Speaker 1: beam in dimensions, scanning across your body left or right,

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Speaker 1: top to bottom. The machine uses detectors to see how

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Speaker 1: many of the X rays scatter off of each point

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Speaker 1: of your body. Certain materials like clothing don't cause much

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Speaker 1: scatter at all. Skin has a certain characteristic scattering effect,

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Speaker 1: as do different metals and certain kinds of explosives. The

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Speaker 1: machine paints an image of the back scattered results point

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Speaker 1: by point, and an agent looking at that image can

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Speaker 1: see things like metals, ceramics, and explosives attached to a

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Speaker 1: passenger's body. The image that comes back is basically an

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Speaker 1: image of a naked human body. It's a strip search

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Speaker 1: without the stripping. It's fast and efficient. So what's the problem.

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Speaker 1: There are three? Actually, First, many people don't like the

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Speaker 1: idea of having photos of their nake bodies taken by

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Speaker 1: any means. In addition, there are a number of stories

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Speaker 1: of abuse e g. You get attractive women being more

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Speaker 1: likely to be scanned or leaked images. Supposedly impossible, but

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Speaker 1: obviously not since leaked images are on the Internet, and

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Speaker 1: it doesn't help to have the kind of stuff happening. Second,

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Speaker 1: because X rays involve ionizing radiation, many, perhaps most people

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Speaker 1: have health concerns. All you have to do is look

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Speaker 1: at the public reaction around any new nuclear power plant

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Speaker 1: or the public acceptance of sunscreens to understand these concerns,

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Speaker 1: even if the experts and the t s A say

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Speaker 1: the machines are safe. The third problem is the perception

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Speaker 1: that it's much ado about nothing, that the t s

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Speaker 1: A represents security theater rather than actual security. This idea

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Speaker 1: first took root because the t s A has not

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Speaker 1: traditionally been very proactive. A terrorist had to bring explosives

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Speaker 1: in the soles of his shoes before the t s

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Speaker 1: A scan shoes. A terrorist had to bring innocent looking

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Speaker 1: liquids to mix a bomb in the air before liquids

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Speaker 1: were prohibited. Printer cartridges were not banned until explosives showed

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Speaker 1: up in printer cartridges, and millions of people get onto

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Speaker 1: subways every day without any screening at all, and that

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Speaker 1: seems to work all right. In the case of the

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Speaker 1: back scatter scanners, the t s A actually is being proactive.

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Speaker 1: It is plugging a security hole before anyone exploits it.

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Speaker 1: But in doing that, the t s A has met

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Speaker 1: with significant resistance. And there's another problem that no one's

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Speaker 1: really discussing right now. A passenger who is striped search

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Speaker 1: still has a currently undetectable way to bring in explosives.

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Speaker 1: The passenger could swallow plastic explosives wrapped in rubber or

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Speaker 1: plastic along with a detonator. The human stomach can hold

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Speaker 1: a couple liters of food and is fairly resilient. One

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Speaker 1: person was known to swallow seventy eight forks and spoons

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Speaker 1: before having to see the doctor. There's no easy way

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Speaker 1: right now to detect this approach short of medical X

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Speaker 1: rays or ultrasound. That leaves us with our current spectrum

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Speaker 1: of choices. At one end of the spectrum, we could

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Speaker 1: let passengers walk onto airplanes like we let them walk

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Speaker 1: onto subway trains, zero security of any kind. At the

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Speaker 1: other end of the spectrum, we could give naked passengers

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Speaker 1: full body cat scans before every flight. Somewhere in the

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Speaker 1: middle is a level of security that the majority of

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Speaker 1: passengers will willingly accept. Apparently, full body X rays scanners

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Speaker 1: maybe a little beyond that limit at this moment in history.

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Speaker 1: For moral this and thousands of other topics. Does that.

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